net/rxrpc/output.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* RxRPC packet transmission
   3  *
   4  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   5  * Written by David Howells (dhowells@redhat.com)
   6  */
   7
   8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   9
  10 #include <linux/net.h>
  11 #include <linux/gfp.h>
  12 #include <linux/skbuff.h>
  13 #include <linux/export.h>
  14 #include <net/sock.h>
  15 #include <net/af_rxrpc.h>
  16 #include <net/udp.h>
  17 #include "ar-internal.h"
  18
  19 extern int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len);
  20
  21 static ssize_t do_udp_sendmsg(struct socket *sk, struct msghdr *msg, size_t len)
  22 {
  23 #if IS_ENABLED(CONFIG_AF_RXRPC_IPV6)
  24         struct sockaddr *sa = msg->msg_name;
  25
  26         if (sa->sa_family == AF_INET6)
  27                 return udpv6_sendmsg(sk->sk, msg, len);
  28 #endif
  29         return udp_sendmsg(sk->sk, msg, len);
  30 }
  31
  32 struct rxrpc_abort_buffer {
  33         struct rxrpc_wire_header whdr;
  34         __be32 abort_code;
  35 };
  36
  37 static const char rxrpc_keepalive_string[] = "";
  38
  39 /*
  40  * Increase Tx backoff on transmission failure and clear it on success.
  41  */
  42 static void rxrpc_tx_backoff(struct rxrpc_call *call, int ret)
  43 {
  44         if (ret < 0) {
  45                 u16 tx_backoff = READ_ONCE(call->tx_backoff);
  46
  47                 if (tx_backoff < HZ)
  48                         WRITE_ONCE(call->tx_backoff, tx_backoff + 1);
  49         } else {
  50                 WRITE_ONCE(call->tx_backoff, 0);
  51         }
  52 }
  53
  54 /*
  55  * Arrange for a keepalive ping a certain time after we last transmitted.  This
  56  * lets the far side know we're still interested in this call and helps keep
  57  * the route through any intervening firewall open.
  58  *
  59  * Receiving a response to the ping will prevent the ->expect_rx_by timer from
  60  * expiring.
  61  */
  62 static void rxrpc_set_keepalive(struct rxrpc_call *call)
  63 {
  64         unsigned long now = jiffies, keepalive_at = call->next_rx_timo / 6;
  65
  66         keepalive_at += now;
  67         WRITE_ONCE(call->keepalive_at, keepalive_at);
  68         rxrpc_reduce_call_timer(call, keepalive_at, now,
  69                                 rxrpc_timer_set_for_keepalive);
  70 }
  71
  72 /*
  73  * Fill out an ACK packet.
  74  */
  75 static size_t rxrpc_fill_out_ack(struct rxrpc_connection *conn,
  76                                  struct rxrpc_call *call,
  77                                  struct rxrpc_txbuf *txb,
  78                                  rxrpc_seq_t *_hard_ack,
  79                                  rxrpc_seq_t *_top)
  80 {
  81         struct rxrpc_ackinfo ackinfo;
  82         unsigned int tmp;
  83         rxrpc_seq_t hard_ack, top, seq;
  84         int ix;
  85         u32 mtu, jmax;
  86         u8 *ackp = txb->acks;
  87
  88         tmp = atomic_xchg(&call->ackr_nr_unacked, 0);
  89         tmp |= atomic_xchg(&call->ackr_nr_consumed, 0);
  90         if (!tmp && (txb->ack.reason == RXRPC_ACK_DELAY ||
  91                      txb->ack.reason == RXRPC_ACK_IDLE)) {
  92                 rxrpc_inc_stat(call->rxnet, stat_tx_ack_skip);
  93                 return 0;
  94         }
  95
  96         rxrpc_inc_stat(call->rxnet, stat_tx_ack_fill);
  97
  98         /* Barrier against rxrpc_input_data(). */
  99         hard_ack = READ_ONCE(call->rx_hard_ack);
 100         top = smp_load_acquire(&call->rx_top);
 101         *_hard_ack = hard_ack;
 102         *_top = top;
 103
 104         txb->ack.firstPacket    = htonl(hard_ack + 1);
 105         txb->ack.previousPacket = htonl(call->ackr_highest_seq);
 106         txb->ack.nAcks          = top - hard_ack;
 107
 108         if (txb->ack.nAcks) {
 109                 seq = hard_ack + 1;
 110                 do {
 111                         ix = seq & RXRPC_RXTX_BUFF_MASK;
 112                         if (call->rxtx_buffer[ix])
 113                                 *ackp++ = RXRPC_ACK_TYPE_ACK;
 114                         else
 115                                 *ackp++ = RXRPC_ACK_TYPE_NACK;
 116                         seq++;
 117                 } while (before_eq(seq, top));
 118         } else if (txb->ack.reason == RXRPC_ACK_DELAY) {
 119                 txb->ack.reason = RXRPC_ACK_IDLE;
 120         }
 121
 122         mtu = conn->params.peer->if_mtu;
 123         mtu -= conn->params.peer->hdrsize;
 124         jmax = rxrpc_rx_jumbo_max;
 125         ackinfo.rxMTU           = htonl(rxrpc_rx_mtu);
 126         ackinfo.maxMTU          = htonl(mtu);
 127         ackinfo.rwind           = htonl(call->rx_winsize);
 128         ackinfo.jumbo_max       = htonl(jmax);
 129
 130         *ackp++ = 0;
 131         *ackp++ = 0;
 132         *ackp++ = 0;
 133         memcpy(ackp, &ackinfo, sizeof(ackinfo));
 134         return top - hard_ack + 3 + sizeof(ackinfo);
 135 }
 136
 137 /*
 138  * Record the beginning of an RTT probe.
 139  */
 140 static int rxrpc_begin_rtt_probe(struct rxrpc_call *call, rxrpc_serial_t serial,
 141                                  enum rxrpc_rtt_tx_trace why)
 142 {
 143         unsigned long avail = call->rtt_avail;
 144         int rtt_slot = 9;
 145
 146         if (!(avail & RXRPC_CALL_RTT_AVAIL_MASK))
 147                 goto no_slot;
 148
 149         rtt_slot = __ffs(avail & RXRPC_CALL_RTT_AVAIL_MASK);
 150         if (!test_and_clear_bit(rtt_slot, &call->rtt_avail))
 151                 goto no_slot;
 152
 153         call->rtt_serial[rtt_slot] = serial;
 154         call->rtt_sent_at[rtt_slot] = ktime_get_real();
 155         smp_wmb(); /* Write data before avail bit */
 156         set_bit(rtt_slot + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail);
 157
 158         trace_rxrpc_rtt_tx(call, why, rtt_slot, serial);
 159         return rtt_slot;
 160
 161 no_slot:
 162         trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_no_slot, rtt_slot, serial);
 163         return -1;
 164 }
 165
 166 /*
 167  * Cancel an RTT probe.
 168  */
 169 static void rxrpc_cancel_rtt_probe(struct rxrpc_call *call,
 170                                    rxrpc_serial_t serial, int rtt_slot)
 171 {
 172         if (rtt_slot != -1) {
 173                 clear_bit(rtt_slot + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail);
 174                 smp_wmb(); /* Clear pending bit before setting slot */
 175                 set_bit(rtt_slot, &call->rtt_avail);
 176                 trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_cancel, rtt_slot, serial);
 177         }
 178 }
 179
 180 /*
 181  * Send an ACK call packet.
 182  */
 183 static int rxrpc_send_ack_packet(struct rxrpc_local *local, struct rxrpc_txbuf *txb)
 184 {
 185         struct rxrpc_connection *conn;
 186         struct rxrpc_ack_buffer *pkt;
 187         struct rxrpc_call *call = txb->call;
 188         struct msghdr msg;
 189         struct kvec iov[1];
 190         rxrpc_serial_t serial;
 191         rxrpc_seq_t hard_ack, top;
 192         size_t len, n;
 193         int ret, rtt_slot = -1;
 194
 195         if (test_bit(RXRPC_CALL_DISCONNECTED, &call->flags))
 196                 return -ECONNRESET;
 197
 198         conn = call->conn;
 199
 200         msg.msg_name    = &call->peer->srx.transport;
 201         msg.msg_namelen = call->peer->srx.transport_len;
 202         msg.msg_control = NULL;
 203         msg.msg_controllen = 0;
 204         msg.msg_flags   = 0;
 205
 206         if (txb->ack.reason == RXRPC_ACK_PING)
 207                 txb->wire.flags |= RXRPC_REQUEST_ACK;
 208
 209         if (txb->ack.reason == RXRPC_ACK_DELAY)
 210                 clear_bit(RXRPC_CALL_DELAY_ACK_PENDING, &call->flags);
 211         if (txb->ack.reason == RXRPC_ACK_IDLE)
 212                 clear_bit(RXRPC_CALL_IDLE_ACK_PENDING, &call->flags);
 213
 214         spin_lock_bh(&call->lock);
 215         n = rxrpc_fill_out_ack(conn, call, txb, &hard_ack, &top);
 216         spin_unlock_bh(&call->lock);
 217         if (n == 0) {
 218                 kfree(pkt);
 219                 return 0;
 220         }
 221
 222         iov[0].iov_base = &txb->wire;
 223         iov[0].iov_len  = sizeof(txb->wire) + sizeof(txb->ack) + n;
 224         len = iov[0].iov_len;
 225
 226         serial = atomic_inc_return(&conn->serial);
 227         txb->wire.serial = htonl(serial);
 228         trace_rxrpc_tx_ack(call->debug_id, serial,
 229                            ntohl(txb->ack.firstPacket),
 230                            ntohl(txb->ack.serial), txb->ack.reason, txb->ack.nAcks);
 231         if (txb->ack_why == rxrpc_propose_ack_ping_for_lost_ack)
 232                 call->acks_lost_ping = serial;
 233
 234         if (txb->ack.reason == RXRPC_ACK_PING)
 235                 rtt_slot = rxrpc_begin_rtt_probe(call, serial, rxrpc_rtt_tx_ping);
 236
 237         rxrpc_inc_stat(call->rxnet, stat_tx_ack_send);
 238
 239         iov_iter_kvec(&msg.msg_iter, WRITE, iov, 1, len);
 240         ret = do_udp_sendmsg(conn->params.local->socket, &msg, len);
 241         call->peer->last_tx_at = ktime_get_seconds();
 242         if (ret < 0)
 243                 trace_rxrpc_tx_fail(call->debug_id, serial, ret,
 244                                     rxrpc_tx_point_call_ack);
 245         else
 246                 trace_rxrpc_tx_packet(call->debug_id, &txb->wire,
 247                                       rxrpc_tx_point_call_ack);
 248         rxrpc_tx_backoff(call, ret);
 249
 250         if (call->state < RXRPC_CALL_COMPLETE) {
 251                 if (ret < 0)
 252                         rxrpc_cancel_rtt_probe(call, serial, rtt_slot);
 253                 rxrpc_set_keepalive(call);
 254         }
 255
 256         kfree(pkt);
 257         return ret;
 258 }
 259
 260 /*
 261  * ACK transmitter for a local endpoint.  The UDP socket locks around each
 262  * transmission, so we can only transmit one packet at a time, ACK, DATA or
 263  * otherwise.
 264  */
 265 void rxrpc_transmit_ack_packets(struct rxrpc_local *local)
 266 {
 267         LIST_HEAD(queue);
 268         int ret;
 269
 270         trace_rxrpc_local(local->debug_id, rxrpc_local_tx_ack,
 271                           refcount_read(&local->ref), NULL);
 272
 273         if (list_empty(&local->ack_tx_queue))
 274                 return;
 275
 276         spin_lock_bh(&local->ack_tx_lock);
 277         list_splice_tail_init(&local->ack_tx_queue, &queue);
 278         spin_unlock_bh(&local->ack_tx_lock);
 279
 280         while (!list_empty(&queue)) {
 281                 struct rxrpc_txbuf *txb =
 282                         list_entry(queue.next, struct rxrpc_txbuf, tx_link);
 283
 284                 ret = rxrpc_send_ack_packet(local, txb);
 285                 if (ret < 0 && ret != -ECONNRESET) {
 286                         spin_lock_bh(&local->ack_tx_lock);
 287                         list_splice_init(&queue, &local->ack_tx_queue);
 288                         spin_unlock_bh(&local->ack_tx_lock);
 289                         break;
 290                 }
 291
 292                 list_del_init(&txb->tx_link);
 293                 rxrpc_put_call(txb->call, rxrpc_call_put);
 294                 rxrpc_put_txbuf(txb, rxrpc_txbuf_put_ack_tx);
 295         }
 296 }
 297
 298 /*
 299  * Send an ABORT call packet.
 300  */
 301 int rxrpc_send_abort_packet(struct rxrpc_call *call)
 302 {
 303         struct rxrpc_connection *conn;
 304         struct rxrpc_abort_buffer pkt;
 305         struct msghdr msg;
 306         struct kvec iov[1];
 307         rxrpc_serial_t serial;
 308         int ret;
 309
 310         /* Don't bother sending aborts for a client call once the server has
 311          * hard-ACK'd all of its request data.  After that point, we're not
 312          * going to stop the operation proceeding, and whilst we might limit
 313          * the reply, it's not worth it if we can send a new call on the same
 314          * channel instead, thereby closing off this call.
 315          */
 316         if (rxrpc_is_client_call(call) &&
 317             test_bit(RXRPC_CALL_TX_LAST, &call->flags))
 318                 return 0;
 319
 320         if (test_bit(RXRPC_CALL_DISCONNECTED, &call->flags))
 321                 return -ECONNRESET;
 322
 323         conn = call->conn;
 324
 325         msg.msg_name    = &call->peer->srx.transport;
 326         msg.msg_namelen = call->peer->srx.transport_len;
 327         msg.msg_control = NULL;
 328         msg.msg_controllen = 0;
 329         msg.msg_flags   = 0;
 330
 331         pkt.whdr.epoch          = htonl(conn->proto.epoch);
 332         pkt.whdr.cid            = htonl(call->cid);
 333         pkt.whdr.callNumber     = htonl(call->call_id);
 334         pkt.whdr.seq            = 0;
 335         pkt.whdr.type           = RXRPC_PACKET_TYPE_ABORT;
 336         pkt.whdr.flags          = conn->out_clientflag;
 337         pkt.whdr.userStatus     = 0;
 338         pkt.whdr.securityIndex  = call->security_ix;
 339         pkt.whdr._rsvd          = 0;
 340         pkt.whdr.serviceId      = htons(call->service_id);
 341         pkt.abort_code          = htonl(call->abort_code);
 342
 343         iov[0].iov_base = &pkt;
 344         iov[0].iov_len  = sizeof(pkt);
 345
 346         serial = atomic_inc_return(&conn->serial);
 347         pkt.whdr.serial = htonl(serial);
 348
 349         iov_iter_kvec(&msg.msg_iter, WRITE, iov, 1, sizeof(pkt));
 350         ret = do_udp_sendmsg(conn->params.local->socket, &msg, sizeof(pkt));
 351         conn->params.peer->last_tx_at = ktime_get_seconds();
 352         if (ret < 0)
 353                 trace_rxrpc_tx_fail(call->debug_id, serial, ret,
 354                                     rxrpc_tx_point_call_abort);
 355         else
 356                 trace_rxrpc_tx_packet(call->debug_id, &pkt.whdr,
 357                                       rxrpc_tx_point_call_abort);
 358         rxrpc_tx_backoff(call, ret);
 359         return ret;
 360 }
 361
 362 /*
 363  * send a packet through the transport endpoint
 364  */
 365 int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb,
 366                            bool retrans)
 367 {
 368         enum rxrpc_req_ack_trace why;
 369         struct rxrpc_connection *conn = call->conn;
 370         struct rxrpc_wire_header whdr;
 371         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 372         struct msghdr msg;
 373         struct kvec iov[2];
 374         rxrpc_serial_t serial;
 375         size_t len;
 376         int ret, rtt_slot = -1;
 377
 378         _enter(",{%d}", skb->len);
 379
 380         if (hlist_unhashed(&call->error_link)) {
 381                 spin_lock_bh(&call->peer->lock);
 382                 hlist_add_head_rcu(&call->error_link, &call->peer->error_targets);
 383                 spin_unlock_bh(&call->peer->lock);
 384         }
 385
 386         /* Each transmission of a Tx packet needs a new serial number */
 387         serial = atomic_inc_return(&conn->serial);
 388
 389         whdr.epoch      = htonl(conn->proto.epoch);
 390         whdr.cid        = htonl(call->cid);
 391         whdr.callNumber = htonl(call->call_id);
 392         whdr.seq        = htonl(sp->hdr.seq);
 393         whdr.serial     = htonl(serial);
 394         whdr.type       = RXRPC_PACKET_TYPE_DATA;
 395         whdr.flags      = sp->hdr.flags;
 396         whdr.userStatus = 0;
 397         whdr.securityIndex = call->security_ix;
 398         whdr._rsvd      = htons(sp->hdr._rsvd);
 399         whdr.serviceId  = htons(call->service_id);
 400
 401         if (test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags) &&
 402             sp->hdr.seq == 1)
 403                 whdr.userStatus = RXRPC_USERSTATUS_SERVICE_UPGRADE;
 404
 405         iov[0].iov_base = &whdr;
 406         iov[0].iov_len = sizeof(whdr);
 407         iov[1].iov_base = skb->head;
 408         iov[1].iov_len = skb->len;
 409         len = iov[0].iov_len + iov[1].iov_len;
 410         iov_iter_kvec(&msg.msg_iter, WRITE, iov, 2, len);
 411
 412         msg.msg_name = &call->peer->srx.transport;
 413         msg.msg_namelen = call->peer->srx.transport_len;
 414         msg.msg_control = NULL;
 415         msg.msg_controllen = 0;
 416         msg.msg_flags = 0;
 417
 418         /* If our RTT cache needs working on, request an ACK.  Also request
 419          * ACKs if a DATA packet appears to have been lost.
 420          *
 421          * However, we mustn't request an ACK on the last reply packet of a
 422          * service call, lest OpenAFS incorrectly send us an ACK with some
 423          * soft-ACKs in it and then never follow up with a proper hard ACK.
 424          */
 425         if (whdr.flags & RXRPC_REQUEST_ACK)
 426                 why = rxrpc_reqack_already_on;
 427         else if ((whdr.flags & RXRPC_LAST_PACKET) && rxrpc_to_client(sp))
 428                 why = rxrpc_reqack_no_srv_last;
 429         else if (test_and_clear_bit(RXRPC_CALL_EV_ACK_LOST, &call->events))
 430                 why = rxrpc_reqack_ack_lost;
 431         else if (retrans)
 432                 why = rxrpc_reqack_retrans;
 433         else if (call->cong_mode == RXRPC_CALL_SLOW_START && call->cong_cwnd <= 2)
 434                 why = rxrpc_reqack_slow_start;
 435         else if (call->tx_winsize <= 2)
 436                 why = rxrpc_reqack_small_txwin;
 437         else if (call->peer->rtt_count < 3 && sp->hdr.seq & 1)
 438                 why = rxrpc_reqack_more_rtt;
 439         else if (ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000), ktime_get_real()))
 440                 why = rxrpc_reqack_old_rtt;
 441         else
 442                 goto dont_set_request_ack;
 443
 444         rxrpc_inc_stat(call->rxnet, stat_why_req_ack[why]);
 445         trace_rxrpc_req_ack(call->debug_id, sp->hdr.seq, why);
 446         if (why != rxrpc_reqack_no_srv_last)
 447                 whdr.flags |= RXRPC_REQUEST_ACK;
 448 dont_set_request_ack:
 449
 450         if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
 451                 static int lose;
 452                 if ((lose++ & 7) == 7) {
 453                         ret = 0;
 454                         trace_rxrpc_tx_data(call, sp->hdr.seq, serial,
 455                                             whdr.flags, retrans, true);
 456                         goto done;
 457                 }
 458         }
 459
 460         trace_rxrpc_tx_data(call, sp->hdr.seq, serial, whdr.flags, retrans,
 461                             false);
 462
 463         /* send the packet with the don't fragment bit set if we currently
 464          * think it's small enough */
 465         if (iov[1].iov_len >= call->peer->maxdata)
 466                 goto send_fragmentable;
 467
 468         down_read(&conn->params.local->defrag_sem);
 469
 470         sp->hdr.serial = serial;
 471         smp_wmb(); /* Set serial before timestamp */
 472         skb->tstamp = ktime_get_real();
 473         if (whdr.flags & RXRPC_REQUEST_ACK)
 474                 rtt_slot = rxrpc_begin_rtt_probe(call, serial, rxrpc_rtt_tx_data);
 475
 476         /* send the packet by UDP
 477          * - returns -EMSGSIZE if UDP would have to fragment the packet
 478          *   to go out of the interface
 479          *   - in which case, we'll have processed the ICMP error
 480          *     message and update the peer record
 481          */
 482         rxrpc_inc_stat(call->rxnet, stat_tx_data_send);
 483         ret = do_udp_sendmsg(conn->params.local->socket, &msg, len);
 484         conn->params.peer->last_tx_at = ktime_get_seconds();
 485
 486         up_read(&conn->params.local->defrag_sem);
 487         if (ret < 0) {
 488                 rxrpc_cancel_rtt_probe(call, serial, rtt_slot);
 489                 trace_rxrpc_tx_fail(call->debug_id, serial, ret,
 490                                     rxrpc_tx_point_call_data_nofrag);
 491         } else {
 492                 trace_rxrpc_tx_packet(call->debug_id, &whdr,
 493                                       rxrpc_tx_point_call_data_nofrag);
 494         }
 495
 496         rxrpc_tx_backoff(call, ret);
 497         if (ret == -EMSGSIZE)
 498                 goto send_fragmentable;
 499
 500 done:
 501         if (ret >= 0) {
 502                 if (whdr.flags & RXRPC_REQUEST_ACK) {
 503                         call->peer->rtt_last_req = skb->tstamp;
 504                         if (call->peer->rtt_count > 1) {
 505                                 unsigned long nowj = jiffies, ack_lost_at;
 506
 507                                 ack_lost_at = rxrpc_get_rto_backoff(call->peer, false);
 508                                 ack_lost_at += nowj;
 509                                 WRITE_ONCE(call->ack_lost_at, ack_lost_at);
 510                                 rxrpc_reduce_call_timer(call, ack_lost_at, nowj,
 511                                                         rxrpc_timer_set_for_lost_ack);
 512                         }
 513                 }
 514
 515                 if (sp->hdr.seq == 1 &&
 516                     !test_and_set_bit(RXRPC_CALL_BEGAN_RX_TIMER,
 517                                       &call->flags)) {
 518                         unsigned long nowj = jiffies, expect_rx_by;
 519
 520                         expect_rx_by = nowj + call->next_rx_timo;
 521                         WRITE_ONCE(call->expect_rx_by, expect_rx_by);
 522                         rxrpc_reduce_call_timer(call, expect_rx_by, nowj,
 523                                                 rxrpc_timer_set_for_normal);
 524                 }
 525
 526                 rxrpc_set_keepalive(call);
 527         } else {
 528                 /* Cancel the call if the initial transmission fails,
 529                  * particularly if that's due to network routing issues that
 530                  * aren't going away anytime soon.  The layer above can arrange
 531                  * the retransmission.
 532                  */
 533                 if (!test_and_set_bit(RXRPC_CALL_BEGAN_RX_TIMER, &call->flags))
 534                         rxrpc_set_call_completion(call, RXRPC_CALL_LOCAL_ERROR,
 535                                                   RX_USER_ABORT, ret);
 536         }
 537
 538         _leave(" = %d [%u]", ret, call->peer->maxdata);
 539         return ret;
 540
 541 send_fragmentable:
 542         /* attempt to send this message with fragmentation enabled */
 543         _debug("send fragment");
 544
 545         down_write(&conn->params.local->defrag_sem);
 546
 547         sp->hdr.serial = serial;
 548         smp_wmb(); /* Set serial before timestamp */
 549         skb->tstamp = ktime_get_real();
 550         if (whdr.flags & RXRPC_REQUEST_ACK)
 551                 rtt_slot = rxrpc_begin_rtt_probe(call, serial, rxrpc_rtt_tx_data);
 552
 553         switch (conn->params.local->srx.transport.family) {
 554         case AF_INET6:
 555         case AF_INET:
 556                 ip_sock_set_mtu_discover(conn->params.local->socket->sk,
 557                                 IP_PMTUDISC_DONT);
 558                 rxrpc_inc_stat(call->rxnet, stat_tx_data_send_frag);
 559                 ret = do_udp_sendmsg(conn->params.local->socket, &msg, len);
 560                 conn->params.peer->last_tx_at = ktime_get_seconds();
 561
 562                 ip_sock_set_mtu_discover(conn->params.local->socket->sk,
 563                                 IP_PMTUDISC_DO);
 564                 break;
 565
 566         default:
 567                 BUG();
 568         }
 569
 570         if (ret < 0) {
 571                 rxrpc_cancel_rtt_probe(call, serial, rtt_slot);
 572                 trace_rxrpc_tx_fail(call->debug_id, serial, ret,
 573                                     rxrpc_tx_point_call_data_frag);
 574         } else {
 575                 trace_rxrpc_tx_packet(call->debug_id, &whdr,
 576                                       rxrpc_tx_point_call_data_frag);
 577         }
 578         rxrpc_tx_backoff(call, ret);
 579
 580         up_write(&conn->params.local->defrag_sem);
 581         goto done;
 582 }
 583
 584 /*
 585  * reject packets through the local endpoint
 586  */
 587 void rxrpc_reject_packets(struct rxrpc_local *local)
 588 {
 589         struct sockaddr_rxrpc srx;
 590         struct rxrpc_skb_priv *sp;
 591         struct rxrpc_wire_header whdr;
 592         struct sk_buff *skb;
 593         struct msghdr msg;
 594         struct kvec iov[2];
 595         size_t size;
 596         __be32 code;
 597         int ret, ioc;
 598
 599         _enter("%d", local->debug_id);
 600
 601         iov[0].iov_base = &whdr;
 602         iov[0].iov_len = sizeof(whdr);
 603         iov[1].iov_base = &code;
 604         iov[1].iov_len = sizeof(code);
 605
 606         msg.msg_name = &srx.transport;
 607         msg.msg_control = NULL;
 608         msg.msg_controllen = 0;
 609         msg.msg_flags = 0;
 610
 611         memset(&whdr, 0, sizeof(whdr));
 612
 613         while ((skb = skb_dequeue(&local->reject_queue))) {
 614                 rxrpc_see_skb(skb, rxrpc_skb_seen);
 615                 sp = rxrpc_skb(skb);
 616
 617                 switch (skb->mark) {
 618                 case RXRPC_SKB_MARK_REJECT_BUSY:
 619                         whdr.type = RXRPC_PACKET_TYPE_BUSY;
 620                         size = sizeof(whdr);
 621                         ioc = 1;
 622                         break;
 623                 case RXRPC_SKB_MARK_REJECT_ABORT:
 624                         whdr.type = RXRPC_PACKET_TYPE_ABORT;
 625                         code = htonl(skb->priority);
 626                         size = sizeof(whdr) + sizeof(code);
 627                         ioc = 2;
 628                         break;
 629                 default:
 630                         rxrpc_free_skb(skb, rxrpc_skb_freed);
 631                         continue;
 632                 }
 633
 634                 if (rxrpc_extract_addr_from_skb(&srx, skb) == 0) {
 635                         msg.msg_namelen = srx.transport_len;
 636
 637                         whdr.epoch      = htonl(sp->hdr.epoch);
 638                         whdr.cid        = htonl(sp->hdr.cid);
 639                         whdr.callNumber = htonl(sp->hdr.callNumber);
 640                         whdr.serviceId  = htons(sp->hdr.serviceId);
 641                         whdr.flags      = sp->hdr.flags;
 642                         whdr.flags      ^= RXRPC_CLIENT_INITIATED;
 643                         whdr.flags      &= RXRPC_CLIENT_INITIATED;
 644
 645                         iov_iter_kvec(&msg.msg_iter, WRITE, iov, ioc, size);
 646                         ret = do_udp_sendmsg(local->socket, &msg, size);
 647                         if (ret < 0)
 648                                 trace_rxrpc_tx_fail(local->debug_id, 0, ret,
 649                                                     rxrpc_tx_point_reject);
 650                         else
 651                                 trace_rxrpc_tx_packet(local->debug_id, &whdr,
 652                                                       rxrpc_tx_point_reject);
 653                 }
 654
 655                 rxrpc_free_skb(skb, rxrpc_skb_freed);
 656         }
 657
 658         _leave("");
 659 }
 660
 661 /*
 662  * Send a VERSION reply to a peer as a keepalive.
 663  */
 664 void rxrpc_send_keepalive(struct rxrpc_peer *peer)
 665 {
 666         struct rxrpc_wire_header whdr;
 667         struct msghdr msg;
 668         struct kvec iov[2];
 669         size_t len;
 670         int ret;
 671
 672         _enter("");
 673
 674         msg.msg_name    = &peer->srx.transport;
 675         msg.msg_namelen = peer->srx.transport_len;
 676         msg.msg_control = NULL;
 677         msg.msg_controllen = 0;
 678         msg.msg_flags   = 0;
 679
 680         whdr.epoch      = htonl(peer->local->rxnet->epoch);
 681         whdr.cid        = 0;
 682         whdr.callNumber = 0;
 683         whdr.seq        = 0;
 684         whdr.serial     = 0;
 685         whdr.type       = RXRPC_PACKET_TYPE_VERSION; /* Not client-initiated */
 686         whdr.flags      = RXRPC_LAST_PACKET;
 687         whdr.userStatus = 0;
 688         whdr.securityIndex = 0;
 689         whdr._rsvd      = 0;
 690         whdr.serviceId  = 0;
 691
 692         iov[0].iov_base = &whdr;
 693         iov[0].iov_len  = sizeof(whdr);
 694         iov[1].iov_base = (char *)rxrpc_keepalive_string;
 695         iov[1].iov_len  = sizeof(rxrpc_keepalive_string);
 696
 697         len = iov[0].iov_len + iov[1].iov_len;
 698
 699         _proto("Tx VERSION (keepalive)");
 700
 701         iov_iter_kvec(&msg.msg_iter, WRITE, iov, 2, len);
 702         ret = do_udp_sendmsg(peer->local->socket, &msg, len);
 703         if (ret < 0)
 704                 trace_rxrpc_tx_fail(peer->debug_id, 0, ret,
 705                                     rxrpc_tx_point_version_keepalive);
 706         else
 707                 trace_rxrpc_tx_packet(peer->debug_id, &whdr,
 708                                       rxrpc_tx_point_version_keepalive);
 709
 710         peer->last_tx_at = ktime_get_seconds();
 711         _leave("");
 712 }